1. Field of the Invention
The present invention relates to a transfer tail forming apparatus for weft feeders which forms a transfer tail automatically by connecting a tail end of a weft feeder now in use with a leading end of a preliminary weft feeder to be used next, for the purpose of changing feeders for the supply of weft to a weaving machine from one to another.
2. Description of the Related Art
In a shuttle-free weaving machine including a jet loom, weft is fed from a weft feeder (hereinafter referred to simply as "feeder") mounted on a feeder stand. When the whole quantity of weft on a single feeder has been consumed, it is necessary to replace the feeder with a new one. As a technique for omitting the weaving machine suspension time during the said replacement there is widely used an automatic feeder change-over technique using a so-called transfer tail.
If a winding start end (hereinafter referred to as "tail end") of a feeder which is supplying weft (hereinafter referred to as "feeder now in use") is connected with a winding terminal end (hereinafter referred to as "leading end") of a feeder to be used next ("preliminary feeder", hereinafter) which is disposed in parallel with the feeder now in use, and thus both yarn ends are connected together through a socalled transfer tail, the weft source will automatically shift to the preliminary feeder when the whole quantity of weft on the feeder now in use has been consumed. Consequently, it is possible to completely omit the suspension of a weaving machine caused by the replacement of feeders. The remaining empty bobbin after the consumption of the total quantity of weft is replaced with another new feeder until the feeder which has newly come to be used as the feeder now in use is consumed in the whole quantity, and this another new feeder is used as a preliminary feeder, with a transfer tail formed between it and the feeder now in use in the same manner as above.
In changing feeders from one to another using such transfer tail, it is more convenient to use an automatic weft threading apparatus (see, for example, Japanese Patent Laid Open No. 47849/986). The technique disclosed therein is for coping with the case where weft fed from a feeder now in use has broken in an intermediate stage of consumption of the feeder. According to the said technique, an automatic threading apparatus is moved from a weaving machine side closer to a transfer tail which has been positioned and held in a predetermined position, and the feeder now in use-side of the transfer tail is cut. In this construction, a leading end of a preliminary feeder is subjected to threading automatically up to a weft measuring and storing apparatus of the weaving machine. As a result, even when the supply of weft stops upon breakage of the weft from the feeder now in use, the weaving machine can continue the operation smoothly under the supply of weft from the preliminary feeder upon completion of the operation of the automatic threading apparatus.
According to such prior art, since the change-over from the feeder now in use to the preliminary feeder is performed without suspension of the operation of the weaving machine, so it is possible to improve the operating efficiency of the weaving machine. In many cases, however, the transfer tail is formed by manual operation of a weaver, so the problem that the weaver's work in the feeder replacement becomes excessive has so far been unavoidable. On the other hand, leading and tail ends of feeders used for forming the transfer tail are suspended free from the feeders and in this state the feeders are conveyed to feeder stands, so there remains an unnecessary work required for the operator also in taking out the leading end from the preliminary feeder.
For the above reason, in the case of planning an automation system for the operations of conveyance and replacement of feeders in a factory, it has been strongly desired to also automate the transfer tail forming operation. But no technique capable of meeting this demand has been known.